King may be most identified with his "I Have a Dream" speech, which he delivered on Aug. 28, 1963, from the steps of the Lincoln Memorial on the National Mall, not far from where the Martin Luther King Jr. memorial now stands. In that electrifying address, King traced the struggle for racial equality from the time of slavery through segregation and painted his vision for a better nation.

Much of the progress made toward fulfilling King's vision has been accomplished through the actions of ordinary citizens who over the years have taken to heart King's call to action: "Life's most persistent and urgent question is: 'What are you doing for others?' "